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D. B. STROPE. PNEUMATIC SPRING,

No. 65,135. Patented May '28, 1867.

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1).,3. STROPE, O L-F R W 'N'E, INDIANA.

Letters 1 cm 2%.65435, dated May 28, 1 867."

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TO ALL WHOMIT MAY CONCERN: v

Be it known that. I, D. B. Srnors, of Fort Wayne, county of Allen, and State of Indiana, have inventeda new and'useful Improvement in Pneumatic Springs and I do herebydeclare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, making part oftliis specification.

' This invention relates to .thatclass of pneumatic springs in which compressed air visusedas the elastic m'e'dium, and oil or other liquid asa cushion for tho piston to rest upon, when, in consequence of the weight placed upon it, the air becomes incapable of supporting such weight.

The invention consists'in the construction of the cylinder and piston in sucha mannterthat the oil and air are introduced to. the outer cylinder through cock and valve provided for the purpose, and from theuce to the piston, which -is hollow, closed at bothits ends, but having an aperture through itslower head, throughwhich its interior communicates withthe reservoir or :space below it in=the outer. cylinder, and through'which theoil and air pass, as above stated, to the interior of the piston.

Figiire 1 of the drawings is an elevation, partly in section, of the entire device, showing the exterior and interior cylinders, with str ding-box and-packing for preventing the escape of air between the surfaces In such cylinders, andalso the bolts for" tightening such packing, the coclr or tubc through which the cylinders are supplied, and'the-stops which prevent the interior cylinder from being forced out of the outer ,one when the weight is removed from the spring. a

Figure 2is an end view of the interim: cylinder or piston on the line of S T in fig. 1, showing the aperture through which it is supplied with air. i

A is the outer cylinder, having its upper end enlarged to form a packing-box for the reception of suitable packing, and is provided with a flange through which bolts pass for tightening such packing. B is the'piston, which'moves vertically within the cylinder and passes through the packing-box and packing above referred to, and projects above all to receive the load which is to be placed upon it. C isthe gland for compressing the packing within the packing-hon. I'is the fibrous packing, of hemp, flax, or other fibrous material. E is 'a brass or other suitable metallic ring: placed underneath the fibrous packing. F is a packing-ring, of rubber, leather, or other suitable material, placed beneath the metallic ring and the bottomiof the packing-boar. This ring has a lip or flange turned down upon its inner periphery in such a manner that when air is compresscd into the outer cylinderit will press against the lower edge of and behind the flange, and thus prevent the escape of the air by'keeping snidflange in close contact with the -piston. v H are ribs or bearers placed within the piston for the purpose of strengthening its lower head, and similar ones may be placed upon its upper l 1ead if found desirable. K are: studs, which have a collar formed upon the lower portion of them, with another section extending below such collar, of suflicient length to allow of their being passed through thelowe'r head of the outer cylinder, and of their receiving a nut outside of said cylinder for keeping them in their position and making a tightjoint around them to prevent" the escape of the contents of the cylinder. These studs also pass up through the lower head of thepiston, but fit therein so loosely as to permit of its moving freely up and i down thereon. Upon the upper end 'of these studs, and within the piston, nuts are secured, which are to prevent the piston from being forced. out of the cylinder whenthe same is filled .with the requisite pressure of air, and when from any cause the load upon such piston is removed. D is'an additional, packing placed in a recess formed in a projection upon the upper-or outer portion of the cylinder, and is designed bothcas an additional securityagaiust leakage of air and as a guide at the piston. L are bolts with nut's'upon them, which pass through flanges Lpon the upper end of the outercylinder and vupon-the gland, for the purpose of compressing the packing, above described. 'G is a cock placed near the lower head of the outer cylinder, having its key y of usual cons ction, for shutting oii' communication hetweenthe atmosphere and the interior of thec'ylinder. M is a valve d in connection with the above-described cock, and is intended as an additional security 'against leakage. Th construction of this valve is such that when it is desirable to fill the-outer cylinder, und 'the passage throu'g a the hey of. the cock: has been'so placed as to register withthe passage in'its body, the valve will be forced against its inner vent and the air will pass around it and through apertures in its inner vent into the cylinder; butwhen the pressure from without is severedit will close against its outer vent, and then, when the key, has been again turned in the cock, so as to close the aperture through it, a double security against leakage is afi'orded. l

The operation of this device is as follows: The parts having been constructed and placed as above described,

a quantity of oil, say two gallons, more or less, according tothe dimensions of the cylinder and piston, (the lower end of the piston should always be'siibmerged in oil or other liquid,) is passed through the cock arid valve into the-cylinder, afte iivhich the air-compressing device, which is usually an air-pump, is applied to the outer end of the cock, or to a flexible tube or hose attached thereto, and air is forced in until the requisite pressure is obtained, when the key in the cock is closed and the valve allowed to close against its outer vent, as above described. This being done, the spring is ready for usc,-.and may be applied to railroad cars, locomotives, land carriages, and to any other position where it is necessary to. support heavyweights upon an elastic medium.

Some of the advantages claimed for this springnre, thatowing to its freedom from liability to leak, in

consequence of the arrangement of the packing, it may be manufactured and filled at ,any place, and transported to any other place for use, and be ready for immediate application upon its arrival. Another and probably'the greatest advantage is, that 'oiving to its peculiar construction it never loses its elasticity, for the reason that when the load placed upon it becomes so great as to force the piston down into the oil in the outer cylinder the piston is filled with air and the oil will be forced into the piston, and then further compresses the air containcd'therein, thus, under the most unfavorable circumstances, furnishing'an elastic spring.

Having thus described my invention, what I claim, and desire ,to secure by Letters Patent, is-

1. The construction and arrangement of the hollow piston, in its relation to the oil contained in the reservoir or outer cylinder, in the manner andfor the purpose herein described.

2. I claim the combination of the packing D/dastic-packing I, metallic packing-ring E, and elastic flange 7 or packing F, with the gland C and piston B.

3. I'claim the combination of the studs K, cylinder A, and piston B, substantially as shown and described. 4. I claim the combination of the cock G, valve M, and cylinder A, when arranged subst-antiallyas shown and described.

In testimony whereof I have signed my name to this specification in thepresenee of two subscribing witnesses.

' 1). B. STRQPE.

Witnesses:

Jon: D. BLOOR, v Jenn S. HOLTJNCSHEAD. 

